fix pyreader return empty array as None in paddle 1.5

fix #151
paddle 1.4 does not occur this problem

ERNIE/finetune/classifier.py

@@ -177,6 +177,8 @@ def evaluate(exe, test_program, test_pyreader, graph_vars, eval_phase):
             total_acc += np.sum(np_acc * np_num_seqs)
             total_num_seqs += np.sum(np_num_seqs)
             labels.extend(np_labels.reshape((-1)).tolist())
+            if np_qids is None:
+                np_qids = np.array([])
             qids.extend(np_qids.reshape(-1).tolist())
             scores.extend(np_probs[:, 1].reshape(-1).tolist())
             np_preds = np.argmax(np_probs, axis=1).astype(np.float32)

ERNIE/reader/task_reader.py

@@ -238,7 +238,7 @@ class ClassifyReader(BaseReader):
         batch_labels = [record.label_id for record in batch_records]
         batch_labels = np.array(batch_labels).astype("int64").reshape([-1, 1])
 
-        if batch_records[0].qid:
+        if batch_records[0].qid is not None:
             batch_qids = [record.qid for record in batch_records]
             batch_qids = np.array(batch_qids).astype("int64").reshape([-1, 1])
         else: